Discontinuous absorption or adsorption cold machine



Jan. 14, 1936 s. LINDEBERG 2,027,693

DISCONTINUOUS ABSORPTION OR ADSORPTION COLD MACHINE Filed May 12, 1934Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE DISCONTINUOUSABSORPTION OR ADSORP- TION COLD MACHINE Sweden Application May 12, 1934,Serial No. 725,381 In Sweden May 15, 1933 Claims.

The invention is for improvements in and relating to discontinuousabsorption or adsorption cold machines of the type in which a heatingperiod is followed by a cold period, the cold period by a heating periodand so on and which comprise a generator for driving off a cold medium,means for condensing the cold medium vapours, a refrigerator forevaporating the liquid cold medium and means for supplying heat to thegenerator during the heating period. The generator may also act asabsorber or a separate absorber may be provided. It has already beensuggested to provide means responsive to the temperature of therefrigerator for starting the heating period when the temperature of therefrigerator rises above a predetermined value and means responsive tothe temperature of the generator for terminating the heating period whenthe temperature of the generator rises above a predetermined value.These means are interdependent on each other in such manner that heat issupplied to the generator only when permitted by both means, whereaseach means by itself is effective for cutting off the supply of heat tothe generator. Thus each of said means responsive to the temperatures ofthe refrigerator and the generator has an effective state in which itpermits heat being supplied to the generator and an ineffective state inwhich it cuts off the supply of heat to the generator. The 1cycle ofoperations in such a machine is as folows.

When the temperature of the refrigerator rises above a certain value, i.e. when it becomes necessary to produce cold, the means responsive tothe temperature of the refrigerator becomes effective for permittingheat being supplied to the generator. It is assumed that the meansresponsive to the temperature of the generator already is in a statewhich permits heat being supplied to the generator. The heating periodthus begins and lasts until the temperature of the generator has reacheda certain value when I the generator until the temperature of therefrigerator has again risen above a certain value.

However, when the cold period is commenced the temperature of thegenerator also begins to fall and if the means responsive to thetemperature of the generator should become effective for admitting heatto the generator before the sup- 5 ply of heat has been cut off by themeans responsive to the temperature of the refrigerator, then a newheating period is started before the cold period is at an end.

The invention has for its object to avoid this difliculty by providingmeans operative to prevent the said means responsive to the temperatureof the generator from starting a heating period, after a cold period hascommenced, until started by the said means responsive to the temperatureof the refrigerator.

The annexed drawing shows some forms of embodiment of an arrangementaccording to this invention.

In the drawing Fig. 1 shows diagrammatically one form having electricalheating means for the generator. Fig. 2 shows a modification of thearrangement according to Fig. 1. Fig. 3 shows diagrammatically a thirdform of embodiment, in which the generator is heated by means of gas,oil or another fluid.

Referring to Fig. 1, 4 designates the refrigerator and 5 the generator,which latter may be combined with the abs -ber into one unit. The saidtwo containers 4 and 5 are in communication with each other by means ofa pipe conduit 6 provided with a condenser 1 in known manner, saidcondenser having an inlet 44 and an outlet 45 for a cooling medium suchas water. Provided in the refrigerator 4 is a thermostat, a temperaturerelay or some other member ID of the well known type responsive to thetemperature of the refrigerator. Provided in the generator there is asecond thermostat ll responsive to the temperature of the generator andof a type similar to the member It. In the form of embodiment shown thethermostat I0 is of the well known thermometer type having a movablemercury column 46 adapted to electrically connect two contacts 41 and48. The thermostat ll 4 contains an expansive medium such as forinstance hydrocarbon and a mercury body 49 moved by said expansivemedium and adapted to connect a contact 50 with either one of twocontacts 5| and 52, respectively.

The contacts 41, 48, 50 and 5| form part of an electric circuit 8, l8,l4 containing a source of current 9 and adapted to supply electricenergy to a heatingelement l2 within the generator 5, whereas thecontacts 41, 48, 50 and 52 55 form part of an electric circuit 8, l8,l9, l4 containing the same source of current 9 as the above mentionedcircuit 8, |8, l4 and besides a heating member I5 located close to thethermostat II and adapted to heat said thermostat as will be moreclearly described below.

The thermostat I0 is adapted to break the heating circuit 8, I8, |2, Hat the contacts 41, 48 at or about at a temperature of plus 5 C. of therefrigerator, while the thermostat H is adapted to break the saidcircuit at the contacts 50, 5| at the end of the boiling period, forinstance at a temperature of about -115-130 C. or at a. highertemperature of the generator.

Upon a boiling period there follows a cold producing period, and it maybe assumed that a cold period is at hand and that the temperature of therefrigerator is below plus 5 C. At this temperature the heating circuit8, I8, l2, I4 is broken at the contacts 41, 48 as indicated in thefigure. At the same time the temperature of the generator is alsorelatively low, and as a consequence the heating circuit is closed atthe contacts 50 and 5| as also indicated in Fig. 1.

At the end of the cold producing period the temperature of therefrigerator begins to rise and when reaching the predetermined value ofplus 5 C. the thermostat l0 closes the circuit at the contacts 41, 48 bythe aid of the mercury column 46, and the heating element I2 will be cutin, thereby starting a new boiling period. At the end of this latterperiod, i. e. when the temperature of the generator has reached any ofthe above predetermined values, the mercury body 49 will due to theexpansion of the expansive medium be moved outwards and break theheating circuit at the contact 5|. Upon this a new cold producing periodfollows.

Since during the cold producing period the temperature of the generator4 drops rather rapidly, it may happen that the thermostat II will closethe heating circuit at the contacts 50, 5| at an early part of the coldproducing period, i. e. before the thermostat III has broken the saidcircuit at the contacts 41, 48, which would result in that a boilingperiod would arise, before the cold producing period is at an end, suchan action being obviously very objectionable.

This drawback is avoided according to the present invention by cuttingin the auxiliary heating member l5, which will, irrespective of the dropof temperature of the generator, maintain the temperature of thethermostat H at such a value which will prevent the mercury body 49 ofreestablishing the main heating circuit 8, |8, H at the contacts 50, 5|,before the cold producing period is at an end.

The cutting in of the said heating member 5 takes place at the end ofthe boiling period by the mercury body 49, which when leaving thecontact 5|, connects the contacts 50 and 52 and thereby establishes theauxiliary heating circuit 8, IS, IS and I4 containing the heating memberHi. This circuit is controlled solely by the thermostat IU of therefrigerator 4 and will not be broken, before the cold producing periodis at an end as described above, i. e. when the temperatures of therefrigerator is below plus 5 C. When thus cutting out the heating member|5 the temperature of the thermostat H drops and the mercury body 48 ismoved back due to the contraction of the expansive medium andreestablishes the main heating circuit at the contacts 50 and 5|. Uponthe following closing of the contacts 41 and 48 at the thermostat H1 atthe end of the cold producing period, 1. e. when the temperature of therefrigerator 4 has risen to about plus 5 C., a new boiling period willstart, followed by a new cold producing period and so on, it beingeffectively secured that a new boiling period will not take place beforethe preceding cold producing period is brought to an end.

Fig. 2 shows a somewhat modified arrangement. In this figure, as in Fig.1, 4 designates the refrigerator, 5 the generator, 6 the pipe conduitconnecting the generator and the refrigerator with each other, 1 thecondenser having the inlet 44 and the outlet 45 for a cooling medium, IDthe thermostat responsive to the temperature of the refrigerator, II thethermostat responsive to the temperature of the generator and I2 theheating element of the generator. The thermostats IO and H are shown tobe of the same type as those according to Fig. 1, but may of course asthe latter be of any other known type.

In this form of embodiment the circuit of the heating element |2 of thegenerator 5 is not directly controlled by the thermostats l0 and II, butindirectly by means of a servomotor of the type comprising anelectromagnet as will be dcscribed below.

The contacts 41 and 48 of the thermostat l0 form part of an electriccircuit 20, 2|, 56, 51 and 22 containing the energizing coil 23 of anelectromagnet 24, the armature 25 of which is carried by a tube l1containing a mercury body 58. The tube I! with the mercury body 58,which forms a circuit breaker of known type, is tiltable together withthe armature 25 about a stationary pin 60, the mercury body then movingfrom the one end of the tube to the other in known manner.

Further, the contacts 41 and 48 of the thermostat |0 form part of anelectric circuit 20, 32, 3|, 58, 26 and 22 containing the auxiliaryheating member I5 for the thermostat responsive to the temperature ofthe generator 5.

The contacts 53 and 54 of said latter thermostat form part of anelectric circuit 20, 2|, 28 and 22 containing a resistance 30 of about7000 ohm or more and controlled by the movable mercury body 48 and alsoby the mercury column 46 of the thermostat Ill. The heating element |2of the generator 5 is contained in a circuit 59, 21, 28 and 22controlled by the mercury circuit breaker H, 58.

It may again be assumed that a cold producing period prevails, and thatthe temperature of the refrigerator 4 is below plus 5 C. In this caseall of the above mentioned circuits controlled by the thermostat I0 arebroken, the armature 25 and the circuit breaker I1, 58 obtain theposition shown in the figure and also the circuit of the heating elementI2 is broken at 26, 21. The temperature of the generator 5 is alsocomparatively low and the mercury body 49 of the thermostat makes nocontact at 53 and 54. The cold producing period is going on.

When at the end of the said period the temperature of the refrigeratorrises to the predetermined value of plus 5 C. the mercury column 46 ofthe thermostat l0 makes contact at 41, 48 and closes the circuit 20, 2|,56, 51 and 22 of the magnet coil 23. The electromagnet 24 is energizedand attracts its armature 25, thereby causing the mercury circuitbreaker I1, 58 to tilt, so that the mercury body 58 connects theconductors 26 and 21. As a consequence the circuit 59,-

21, 26 and 22' of the heating element I2 is closed and a boiling periodstarts.

At the end of said latter period, when the temperature of the generator5 has risen to the predetermined value of for instance C., the mercurybody 49 of the thermostat I I makes contact at 53, 54, thereby closingthe circuit 20, 2|, 28 and 22 containing the high resistance 30.Simultaneously with the closing of the said circuit the circuit 20, 2|,56, 51 of the magnet coil 23 will be short-circuited, and as aconsequence the electromagnet 24 will be disenergized, resulting in thatthe armature 25 and the tube l1 will be tilted to the position shown inthe figure, for instance through the action of a spring 6| .as shown,said movement being limited by an abutment 62. In this position of thetube II the circuit 20, 32, 3|, 58, 26 and 22 of the auxiliary heattingmember |5 will be closed, and the temperature of the thermostat II will,irrespective of the drop of temperature of the generator at thebeginning cold producing period, be maintained at a value sufficient tokeep the mercury body 49 in contact with the contacts 53 and 54- andthus to maintain the short-circuiting of the electromagnet circuit, sothat the heating element |2 of the generator 5 cannot be cut in and anew boiling period cannot start. This condition lasts, until the circuitof the heating member i5 is broken by the thermostat I0 at the contacts41, 48, whereupon the mercury body 49 of the thermostat II will due tothe low temperature of the generator return to the position shown in thefigure and break off the short-circuiting of the magnet coil 23, so thata new boiling period can begin, when the cold producing period is at anend and the circuit of the said coil is again closed at the contacts 41,48 of the thermostat I0. During the shortcircuiting period of the magnetcoil 23 the energy in the circuit 20, 2|, 54, 49, 53, 28 and 22 isaccumulated by the resistance 30, which is suiflcient for the relativelyshort time, until the current is broken by the thermostat i0.

According to the above form of embodiment the heating current does notpass through the thermostats, and the current, which passes through thethermostats and serves only as a manoeuvring current for a servomotorsuch as the electromagnet, may be of a lower voltage than the heatingcurrent. The auxiliary heating member |5 may have a very small capacity,so that the heat delivered by the same will have no essential influenceon the course of the cold producing period.

Fig. 3 illustrates a form of embodiment, wherein the heating of thegenerator 5 is brought about by the aid of a fluid, such as gas, oil orany other heating fluid. The said fluid is'conducted to the generator 5through a conduit 36 having a suitable burner 39 for generating a flame38. The generator is provided with a suitable thermostat II a responsiveto the temperature of the generator, and similarly the refrigerator 4 isprovided with a thermostat |0a responsive to the temperature of therefrigerator. The said thermostats comprise containers 63 and 64,respectively, for an expansive medium such as for instance hydrocarbonor a liquid or the like, the containers being connected by means ofpipes 65 and 66, respectively, with the interior of valve casings 61 and68 secured to the fluid conduit 36 and having valve bodies 31 and 35,respectively, movable therein. The valve bodies 31 and 35 areprovidedwith ports 69 and 10, respectively, controlling the passage ofthe fluid through the conduit 36. The valve bodies are moved in the onedirection (downwards) by the action of the expansive medium in thethermostats at certain temperatures of the generator 5 and therefrigerator 4 and are moved in the other direction (upwards) by theaction of springs 1| and 12, respectively. The valve 31 is shown in openposition and is moved to this position by the spring 1|, whereas thevalve 35 is shown in closed position and is moved to such position bythe action of its spring 12. Thus, the expansive medium in thethermostat Ila tends to close the valve 31, Whereas the expansive mediumin the thermostat |||a tends to open the valve 35. In the lower part ofthe valve body 31 there is provided a second port or channel 43 adaptedto bring about a communication between a branch pipe 40 and a pipe 4|having a small auxiliary burner 42 for heating the thermostat Ha, whenthe valve body 31 is in its closed position, in order to maintain thesaid valve body in such position also after the end of a boiling period.The thermostats Illa and Ma are assumed to operate at the temperaturelimits mentioned above in connection with the embodiments according toFigs. 1 and 2.

It may now again be supposed that a cold producing period is going onand that the temperature of the refrigerator 4 is below plus 5 C. Inthis case the valve 35 is held in its closed position as shown by meansof its spring 12, the thermostat |0a being out of action. Also thethermostat Ila is out of action, and the valve 35 is held in its openposition by means of the spring 1|. At the end of the cold producingperiod the temperature of the refrigerator begins to rise and whenreaching the predetermined value of plus 5 C. the thermostat |0a isbrought into action, the expansive medium therein acting on the valvebody 35 and moving it to the open position against the action of thespring 12. In this position they fluid is free to pass to the mainburner 39, and a boiling period starts.

At the end of this period, when the temperature of the generator hasreached the predetermined value of say for instance 115 C., thethermostat Ila is brought into action and closes the valve 31 againstthe action of the spring 1|. Thus, the passage of the fluid is shut miand the boiling period ceases, which results in that the temperature ofthe generator drops, a new cold producing period being now started. Atthe closing of the valve 31 the channel 43 is brought to register withthe openings of the pipes 40 and 4|, and the fluid is delivered to theauxiliary burner 42, which will, irrespective of the drop of temperatureof the generator, maintain the temperature of the thermostat Ila at sucha value that the pressure of the expansive medium keeps the value 31 inits closed position. At the end of the cold producing period, when thetemperature of the refrigerator is below plus 5 C., the expansive mediumin the thermostat Illa is contracted, the valve 35 returns to its closedposition under the action of the spring 12 and shuts off the supply offluid also to the auxiliary burner 42, so that the action of thethermostat ||a ceases. Then the valve 31 is returned to its openposition under the action of the spring 1|, and a new boiling periodwill start, when at .the predetermined temperature of the refrigera- 7tor 4 the valve 35 is again brought to the open position.

In all of the forms of embodiment shown and described the beginning of aboiling period is controlled under all conditions by the thermostat illor Illa in accordance with the temperature prevailing in therefrigerator 4.

Ordinary thermostats or any other members responsive to variations ofthe temperature may be used for controlling the supply of heatingmedium. The said members may actuate the regulating means for theheating medium by the aid of an auxiliary electric current when using anelectric heating current as well as gas or other fluid. Further, theexpansive medium of the thermostat, when using such types of thermostatsneed not directly actuate the regulating means of the heating medium orthe auxiliary current. For instance in thermostats according to Fig. 3the expansive medium may displace a piston or act upon a diaphragm, themovement of which is utilized for adjusting the regulating means. Thefluid supplied through the conduit 36 may instead of a burnable gasconsist of a hot liquid or gas, which gives off its heat to thegenerator and the thermostat.

Further, the invention is not dependent upon the constructive details ofthe cold producing machine and thus is independent of the means forcooling the absorber. The absorber and the generator, which may beplaced adjacent to each other or combined into a commongeneratorabsorber, may thus be combined with any system for cooling withair or liquid. Further the two thermostats may obviously be located atother places than in the refrigerator and the generator, respectively,if they are but made responsive to the temperature of said parts. Thethermostat responsive to the temperature of the refrigerator maytherefore be placed in the cold chamber or in conduits leading from orto the refrigerator. In cold machines heated by oil through a wickburner the wick or the flame may be acted on by the thermostats or thelatter may directly actuate a rack in accordance with the arrangement,by means of which the displaceable valves in Fig. 3 are actuated throughthe thermostats.

What I claim as new and desire to secure by Letters Patent of the UnitedStates of America 1. Discontinuous absorption or adsorption cold machineof the type in which a heating period is followed by a cold period, thecold period by a heating period and so on. including a generator fordriving oil a cold medium, means for condensing the cold medium vapours,a refrigerator for evaporating the liquid cold medium, means forsupplying heat to the generator, means operat ve responsive to thetemperature of the refrigerator to start a heating period when thetemperature of the refrigerator rises above a predetermined value, meansoperative responsive to the temperature of the generator to terminatethe heating period when the temperature of the generator rises above apredetermined value and auxiliary heating means operative to prevent thesaid means responsive to the temperature of the generator from startinga heating period, after a cold period has commenced, until started bythe said means responsive to the temperature of the refrigerator.

2. Discontinuous absorption or adsorption cold machine of the type inwhich a heating period is followed by a cold period, the cold period bya heating period and so on, including a generator'for driving off a coldmedium, means for condensing the cold medium vapours, a refrigerator forevaporating the liquid cold medium, means for supplying heat tothegenerator, means responsive to the temperature'of the refrigeratorand operative to permit heat being supplied to the generator above apredetermined temperature of the refrigerator and to cut off the supplyof heat to the generator below a predetermined temperature of therefrigerator, means responsive to the temperature of the generator andoperative to cut of! the supply of heat to the generator above apredetermined temperature of the generator and auxiliary heating meansoperative to delay the action of the last mentioned means in againbecoming effective for permitting heat being supplied to the generator.

3. Discontinuous absorption or adsorption cold machine of the type inwhich a heating period is followed by a cold period, the cold period bya heating period and so on, including a generator for driving off a coldmedium, means for condensing the cold medium vapours, a refrigerator forevaporating the liquid cold medium,

means for supplying heat to the generator,

means responsive to the temperature of the refrigerator and operative topermit heat being supplied to the generator above a predeterminedtemperature of the refrigerator and to cut of! the supply of heat to thegenerator below a predetermined temperature of the refrigerator, meansresponsive to the temperature of the generator and operative to cut offthe supply of heat to the generator above a predetermined temperature ofthe generator and auxiliary heating means operative to delay the actionof the last mentioned means in again becoming effective for permittingheat being supplied to they generator substantially until the said meansresponsive to the temperature of the refrigerator have cut oi the supplyof heat to the generator.

4. Discontinuous absorption or adsorption cold 1 machine, including agenerator for driving off a cold medium, means for condensing the coldmedium vapours, a refrigerator for evaporating the liquid cold medium,means for supplying heat to the generator, means for controlling themachine of the type in which a heating periodis followed by a coldperiod, the cold period by a heating period and so on, including agenerator for driving off a cold medium, means for condensing the coldmedium vapours, a refrigerator for evaporating the liquid cold medium,means for supplying heat to the generator, means operative responsive tothe temperature of the refrigerator to turn on the supply of heat to thegenerator when the temperature of the refrigerator rises above apredetermined value, means operative responsive to the temperature ofthe generator to cut off the supply of heat to the generator when thetemperature thereof rises above a predetermined value, each of saidmeans responsive to the temperatures of the refrigerator and thegenerator having a state in which it permits heat being supplied to thegenerator and a. state in which it prevents heat being supplied to thegenerator, and auxiliary heating means for said means responsive to thetemperature of the generator operative after the supply of heat to thegenerator has been out off by said latter means at the end of theheating period to maintain the temperature of said means responsive tothe temperature of the generator at the beginning of the cold period anddelay its action in again becoming effective for permitting heat beingsupplied to the gen- 5 erator.

STIG LINDEBERG.

